Field of the Invention
The present invention relates to a surgical method of attachment of a first bony segment in relation with a second bony segment, both segments belonging to a same bone, for osteotomies, and to a method of control of a computer piloted robot and a surgical system for implementing such kind of surgical method.
Description of Related Art
Osteoarthritis is a mechanical abnormality involving degradation of the joints, including articular cartilage and subchondral bone.
This pathology can be treated using different methods. The most common one is the total replacement of the diseased joint with a prosthetic implant. This method is however very degenerative, invasive and sometimes traumatic for the patient.
When this disease is the consequence of a misalignment of a limb, it can be delayed or treated with an opening osteotomy. This surgical procedure aims to rebalance the stress on the diseased joint by realigning the joint centers of the limb (hip, knee and ankle centers for the lower limb and shoulder, elbow and wrist for the upper limb). A partial cut is thus performed on one of the two bones forming the limb (femur or tibia for the lower limb, and, humerus or radius for the upper limb). The deformation is made by rotating the cut bones around a rotation point called “hinge” resulting from the partial cut. Once the alignment has been reached, the two cut bony segments are maintained in the desired position, in most cases, with an osteosynthesis implant.
The Arthrex Company commercializes an osteotomy implant comprising two longitudinal faces, each one being provided with two curved areas spaced apart from each other with a central flat area between them.
To put in place such an implant, the surgeon drills two spaced apart holes in the bone, and then he cuts the bone along the diameter of the two holes, then inserts the implant inside the opening after having distracted the two bony segments and finally fixes it with screws. This implant maintains the relative positions of the two bony segments and avoids the over-thickness of conventional osteotomy plates.
Nevertheless, this way of operating has several drawbacks:                the resulting alignment can be inaccurate and can lead to bad post-operative results since the required correction angle to align the lower limb is planned preoperatively in simple two-dimensions (2D) x-rays and is reported during the surgery with a simple geometric ruler;        the system cannot adjust the alignment of the limb in the three required rotations of the space. Only the alignment in the frontal plane can be realized, the slope (rotation in the sagittal plane) and the coronal rotations cannot be correctly adjusted which can lead also to non-optimal postoperative results;        the surgeon needs to have a large number of implants of different sizes to choose among them the most appropriate to the size and the shape of the hole obtained after distraction of the two bony segments, (ideally one implant per degree or half-degree of opening wedge);        the surgeon may even have some difficulties to find an implant perfectly matching with the hole particularly when the performed hinge does not create a perfect opening axis after distraction;        there is also the risk that the implant enters too deeply between the two bony segments.        